Automated solid-phase catalyzed pre-column derivatization of fatty acids for reversed-phase high-performance liquid...

A method is described to automate the solid phase catalyzed reaction of a carbonyl group with labels containing a bromomethyl group. The acids to be determined must be soluble in an aprotic, non-aqueous reaction medium, such as acetonitrile. Special emphasis is placed on the solubility of the base, which serves as a catalyst. A suspension of potassium carbonate was prepared in acetonitrile. In this way, the effective surface area of the base is drastically enlarged resulting in faster reaction kinetics. The procedure is illustrated with the detection of fatty acids in serum and rat brain tissue with bromomethylmethoxycoumarin as label. The generality of our approach for HPLC determination of carbonyl compounds is discussed.